Preventable hospitalizations, defined as those health conditions for which timely and effective outpatient care can reduce the risks of hospitalization (Billings et al., 1993), increasingly are being used as indicators of access to care. It has been estimated that nearly five million admissions with diagnoses related to potentially preventable conditions occur annually in the United States, admissions that result in over $26.5 billion dollars in health care costs (Agency for Healthcare Research and Quality, 2004). The cost and effort associated with these preventable admissions are a significant resource drain on a health care system already stretched thin. Furthermore, they suggest that opportunities exist to improve outpatient access to care. Conceptual models of access have historically placed great emphasis on individual or market level factors (Anderson and Aday, 1978; Aday and Anderson, 1981). More recent theoretical and policy oriented work has called for the application of organizational frameworks to identify systemic factors that may affect access to care (Gold, 1998). This project will begin to address this gap by examining the relationship between hospital integration, service diversity, and preventable hospitalizations. The central premise of this study is that the costs associated with coordinating resources within and between organizations in a local market effect the number of preventable hospitalizations. Using a resource dependence perspective, this study will argue that hospitals enter into interdependent relationships in response to environmental uncertainty, which increases coordination costs related to monitoring and managing these interdependencies. Higher coordination costs will increase the rate of preventable hospitalizations by diverting resources away from core organizational functions. One response by hospitals to mitigate monitoring costs is the use of bureaucratic controls. This study will be argue that more integrated structures are more likely to utilize such bureaucratic controls and therefore will be more successful at minimizing coordination costs and linking services over time and place. The study has both health care management and policy implications. First, a better understanding of how structural arrangements of hospitals affect preventable hospitalizations may help organizational decision makers understand the strategic options that exist to meet the health care needs of local community residents. Such decisions are likely to become more important as regulatory oversight brings hospital payment into closer alignment with health care outcomes such as "preventable complications" (Rosenthal, 2007). Similarly, policy makers may gain a better understanding of how tightening or loosening regulatory oversight of the structural relationships between hospitals and other types of health care organizations can affect local access to care. For example, the results may inform policy makers about future direction of Stark laws governing physician- hospital relationships. [unreadable] [unreadable] Public Health Relevance: This study will examine the relationship between hospital integration, hospital service diversity, and preventable hospitalizations. Preventable hospitalizations will be used an indicator of local area access to care. In doing so, study will attempt to explain how organizational factors facilitate or impede consumer access to care. [unreadable] [unreadable] [unreadable]